Not everyone shared his enthusiasm, however.
Franco was born and bred in Argentina. He had no ancestral connections with Mexico, arriving in 2003 to play for Monterrey after a move from Buenos Aires club San Lorenzo.
Less than three years later, he was selected to play for the Tricolor by coach Ricardo La Volpe, who himself was born in Argentina and was reserve goalkeeper in his country's 1978 World Cup winning squad.
Although Franco had legitimately obtained a Mexican passport without any special treatment, his selection split Mexican football down the middle.
The 29-year-old is the second naturalised player to be picked by La Volpe, after Brazilian-born midfielder Antonio Naelson, and critics say the pair, who are both in the World Cup squad, are blocking the way for Mexican-born players.
The most outspoken comments have come from former Real Madrid and Mexico striker Hugo Sanchez.
"It's very dangerous because we've already got two or three and that could became four, five or six and then we will reach a moment when the national team is no longer the national team but a team of naturalised players," said Sanchez.
"The players are not to blame, certainly Franco or Zinha (Naelson's nickname)," he added. "It's the people who make the decisions who are responsible.
"That's where the right measures have to be taken, for the good of the Mexican footballer and the good of the Mexican national team."
PURE MEXICANS
"It would be great to win a World Cup with pure Mexicans but how sad it would be if we won it with naturalised players."
Forward Jesus Arellano, who played for Mexico at the last two World Cups, is also against the use of naturalised players.
"Speaking as a Mexican player, some of us don't like the naturalised players in the national team, we'd rather have just Mexicans," he said.
La Volpe remains defiant.
"Most of the strikers who play in Mexico, I would say 80 percent, are foreigners and if one of them is a naturalised Mexican, I don't understand why I can't see what he can do," La Volpe said.
He also had a swipe at club coaches who criticised his selection policy.
Mexico has the richest domestic league in Latin America and attracts players from all over the region, many of whom settle in the country and take out nationality.
"I'd like to see all these coaches who complain about naturalised players field only Mexicans," he said.
La Volpe was supported by Felipe Munoz, president of the Mexican Olympic Committee.
"If the rest of the world is doing it, we have to do it as well and try and benefit ourselves. If they (naturalised players) are better and can displace a Mexican-born player, then that's perfectly correct."
DEBUT GOAL
Spanish-born Carlos Blanco was the first naturalised player to represent Mexico when he took part in the qualifying matches for the 1954 and 1958 World Cups.
Argentine-born Carlos Lara played in the qualifiers for the 1962 World Cup and was followed by Gabriel Caballero, another Argentine-born player, who was included in the 2002 World Cup squad.
Naelson, whose presence in Germany has been threatened by a knee injury, became the first naturalised player to score for Mexico when he was on target in a 3-0 World Cup qualifying win over Trinidad & Tobago in 2004.
Franco, who has left Monterrey to play for Spanish club Villareal, scored on his debut against Guatemala last November and was also on target in the 1-0 friendly win over Ghana in March.
Defiantly, the gruff coach, withstood pressure to include in his World Cup squad the Mexican-born Cuauhtemoc Blanco, who many regard as the country's top player.
He did, however, contemplate selecting Argentine-born Walter Gaitan and encouraged him to take up Mexican nationality.
The resulting furore was such, however, that Gaitan changed his mind and withdrew his application for Mexican nationality at the end of January.
"It's because of the way the media interpreted it, all the hassle," the player said.